The Wrigglesworth Lake showing is located just west of the lake on the southwest corner of Lot 8, 20 kilometres northwest of Victoria.

A band of limestone extends northwest from the southwest corner of Wrigglesworth Lake for 400 metres. The band varies in width from 76 metres at its southeast end to 107 metres at its northwest end. The Malahat fault truncates the southeast end of the band, bringing interbedded ribbon cherts, slates and tuffs of the Jurassic to Cretaceous Leech River Comoplex (Formation) into contact with the limestone. The band is bounded to the southwest by gneissic greenstone of the Colquitz Gneiss and to the northeast by outcrops of the Wark Gneiss. The Wark and Colquitz gneisses are thought to be metamorphic equivalents of mafic and silicic units of the Paleozoic Sicker Group, respectively; the latest metamorphism took place in the Jurassic. A few mafic dykes intrude the limestone.

The limestone is comprised of fine to medium-grained, dark grey to white limestone. Scattered small lenses of chert are present. A chip sample taken across 107 metres of limestone near the northwest end of the band contained 54.5 per cent CaO, 0.44 per cent MgO, 1.50 per cent insolubles, 0.16 per cent R2O3, 0.07 per cent Fe2O3, 0.006 per cent MnO, 0.009 per cent P2O5, 0.01 per cent sulphur, 43.3 per cent ignition loss and 0.11 per cent water (Bulletin 40, page 90).